Limits on f_NL parameters from WMAP 3yr data

TL;DR

This paper analyzes WMAP 3-year data to search for non-Gaussian signals in the cosmic microwave background, setting the tightest bounds to date on the f_NL parameters for local and equilateral shapes.

Contribution

It provides the first tight constraints on local and equilateral non-Gaussianity parameters using WMAP 3-year data, with no evidence of deviation from Gaussianity.

Findings

No significant non-Gaussianity detected.

Bounds on f_NL^local: -36 to 100.

Bounds on f_NL^equil: -256 to 332.

Abstract

We analyze the 3-year WMAP data and look for a deviation from Gaussianity in the form of a 3-point function that has either of the two theoretically motivated shapes: local and equilateral. There is no evidence of departure from Gaussianity and the analysis gives the presently tightest bounds on the parameters f_ NL^local and f_NL^equil., which define the amplitude of respectively the local and the equilateral non-Gaussianity: -36 < f_NL^local < 100, -256 < f_NL^equil. < 332 at 95% C.L.